Diopter and image quality on wide angle zoom?
Posted 15 January 2006 - 05:28 PM
1) According to the formula on the wetpixel dome theory page, I should be using a 4x diopter with the Ike 6" dome. My question is: will using a high quality diopter significantly influence image quality, and will it make it better or worse? Also, would a 4x be better/worse than, say, a 2x?
2) My second question is more technical, and less important. Does using a diopter change the properties of the lens in such a way that a different amount of extension should be used on the dome port?
Thanks for the help!
Posted 15 January 2006 - 11:39 PM
A diopter always reduces the image quality in such a case. A good diopter degrades a bit less than a single lense one. The optimum would be a large dome or a lens that can focus close enough.
There's no need in changing the position of the dome glass (no need for step rings) as long as the dome is at the correct position in the first place.
Posted 16 January 2006 - 09:33 PM
The 16-35 in a #5503.55 6" dome should work well on a cropped sensor camera such as a 20D or digital Rebel.
I have found the combination has problems the full frame 5D. There is a significant problem with refraction at the edges. Hopefully the new biggah 8" dome will prove to be a better optical match on FF.
Posted 17 January 2006 - 09:13 AM
Posted 17 January 2006 - 01:04 PM
Posted 17 January 2006 - 03:19 PM
In my opinion, and I know not all share it, when it comes to wide angle zooms "no dioptre good, use a dioptre better"
Posted 18 January 2006 - 12:10 PM
Having that said, I don’t use dioptres at the moment because I like split shots and I am too lazy to buy some for the time being.